The present invention relates in general to communication systems using transmitters-receivers having automatic alternation control. Such transmitters-receivers operating with single sideband amplitude modulation and incorporating in the transmitter part thereof means for compressing the amplitude of voice modulation signals therein and in the receiver part a voice-noise discriminator for eliminating noise between voice activity periods are known.
At the output of the receiver's demodulator, such known transmitters-receivers provide voice signals of substantially constant amplitude and therefore do not accurately reproduce the changing amplitude levels of voice signals modulating the transmitter.